Problem: Evaluate the following expression when $a = 1$ and $b = 10$. $5$ $a$ $ + 4$ $b$ $ - 5$
Answer: Substitute $1$ for ${a}$ and $10$ for ${b}$ $ = 5{(1)} + 4{(10)} - 5 $ $ = 5 + 40 - 5 $ $ = 40$